A global hypoacetylation of histone H3 and H4, a downregulation in mRNA of histone acetyltransferases (P300, CREBBP), and an increase of sirtuin 1 (histone deacetylase) mRNA level was observed in active SLE CD4+ T lymphocytes in vitro compared with controls [14]. This evidence concerns the gene EP300 and systemic lupus erythematosus.